An application program for formulating a reference material used for presentation, and for displaying the so formulated reference material on the occasion of presentation, is usually employed under a condition in which it is installed on a personal computer. The application program for presentation has the function of saving each page, that is a slide, used for presentation, in one file. In carrying out the presentation, a user boots an application program for presentation and opens a relevant file to carry out the presentation. That is the user is able to sequentially display the slides as the presentation proceeds.
Meanwhile, since the presentation of various reference materials is usually carried out before many viewers, the reference materials to be presented, that is slides, need to be presented at a time to many viewers. So, the presentation is carried out as each slide is demonstrated on a large size screen, using e.g., a projector.
In demonstrating a slide by a projector on a large sized screen, the conventional practice is to convert each slide in the file formulated with the application program for presentation into picture data of a format consistent with e.g., the JPEG (Joint Photographic Experts Group) standard and to display each slide by the projector with the use of the picture data. For converting the file, prepared with the application program for presentation, into picture data, a folder bearing the filename of the file is formulated and, in this folder, the picture data of each slide is stored. The name of the folder is usually formed by letter or character data. That is, the letter or character data, used in the folder name, is prepared with a language supported by an operating system (OS) installed in the personal computer.
However, if a user is to search a folder having stored the picture data of the slide required for the presentations, now to be displayed, it is difficult for the viewer to make retrieval if solely the folder names are resorted to. When the user is unable to find out the data for presentation with solely the folder name, the user has to open the folder to check the picture data in the folder by a laborious operation.
On the other hand, if it is attempted to open a recording medium to check the folder contents, using a device not supporting the letters or characters forming the folder name, the folder name is sometimes displayed in irrelevant letters or characters (so-called garbled letters or characters), with the consequence that the user is unable to distinguish the displayed letters or characters.